After time, pipelines often suffer from corrosion of the inner diameter and/or minor cracking and/or leakage. Such pipelines must often be replaced or rehabilitated. Replacement often involves the movement or destruction of above-ground structures, such as roadways or sidewalks. Rehabilitation, on the other hand, may permit a new inner diameter of the pipe to be created using the existing pipeline as an outer shell, which may eliminate the need to dig up large sections of existing pipeline and/or water mains, and which may involve significant cost savings over replacement.
One form of pipeline rehabilitation involves the installation of a tubular liner inside of a host pipe with hardenable cement mortar (formed from grout) between the tubular liner and the host pipe. However, grout injected between the tubular liner and the host pipe may have a tendency to slide off of the tubular liner and flow down below the tubular liner, thereby inhibiting ideal grout coverage in the uppermost areas between the tubular liner and the pipeline. Also, as the grout is distributed between the liner and the pipeline, entrained or entrapped air due to lack of adequate back pressure can cause defects or gaps in grout coverage.